Telltale switch.



J. HOWLAND.

TBLLTALH SWITCH.

APPLICATION FILED MAR.10, 1914.

Patented Mar. 23, 1915.

WITNESSES- HAS A TTOR/VEY JOHN HOW'LANID, OF SAN ANTONIO, TEXAS.

TELLTALE SWITCH.

Specification of Letters Patent.

Patented Mar. 23, 1915.

Application filed March 10,1914. Serial N 0. 823.752.

To all whom it may concern:

Be it known that I, JOHN HOWLAND, a citizen of the United States ofAmerica, residing in San Antonio, county of Bexar, State of Texas, haveinvented certain new and useful Improvements in Telltale Switches, ofwhich the following is aspecification, reference being had therein tothe accompanying drawings. 4

My invention relates to automatic telltale switches; and has for itsobject the production of a simple switch which, when connected inv anelectric circuit, is adapted to keep the circuit open as long as avacuum is maintained and as soon as the vacuum or suction is relieved toautomatically close the circuit thereby giving notice of the failure tomaintain the vacuum.

The invention is particularly adapted and designed to indicate thereduction in vacuum in systems which it is desired to keep a more orless uniform vacuum such as in fruit dryers, creosoting plants, surfaceand jet condensing for steam plants and the like. The dimensions andproportions of my device to be changed accordingly to suit the variousrequirements.

The invention consists in the novel construction, combination andarrangement of parts, which will be hereinafter described and claimed.

In the accompanying drawing, my. invention is shown in a singleelevation, in which I employ a panel board 1 on which is mounted ametallic tube 2 bent in a semicircular shape and adapted at each end toreceive and support glass tubes 3 and 4:. At the upper end of glass tube3 I provide metal fitting 5 adapted to receive and hold in an adjustedposition an electrode 6. At the top of tube 4 I provide a metal elbow 7and piping 8 with the necessary fittings 25. This piping is connected toa pump suction 9 or other pipe, where a continuous vacuum is desired tobe maintained.

On the panel board 1 I have mounted a switch 10 and connection plugs 11and 12. The switch 10 is provided with three connection screws 13, 1 1,15. In the glass tube 4 an electrode 16 is mounted. This electrode isconnected to switch 10 at screw 15 through wire circuit 17 The electrode6 is connected to switch 10 at 14 through wire circuit 18. Wireconnections 19 and 20 are made respectively between 13 and 12 and 11 and21. The connection 21 being a part of clamp which holds thesemi-circular metal tube 2 to the panel board 1. A standard bell andbattery circuit is connected to plugs 11 and 12.

It will be readily understood that the electrode 6 may be adjusted toany height desired and that the lengths of the tubes 3 and 4 may varydepending upon the service to which the switch is put. At the top oftube 3 the fitting 5 is provided with a T connection 22 and piping witha valve 24 terminating in a funnel 23. Through this connection anydesired amount of mercury may be poured into the tube.

The operation of thetell-tale switch is as follows: The piping 8 isconnected to any pump suction or vacuum 9. The electrode 6 is adjustedso as to be free of the mercury in tube 3 when the proper vacuum isrecorded by the height of the mercury in tube 4:. The arm switch 10 isthrown on contact 14. If for any reason the vacuum fails by the stoppingof the pump or other causes, the mercury in two arms of the U tubeequalizes and 'contacts with the wire or electrode 6 closing thecircuit, ringing the bell, giving notice that attention is necessary.

I wish it distinctly understood that my tell-tale switch hereinillustrated and described, is in the form which I desire to constructit, and that any changes or varia tions may be made as may be convenientor desirable without departing from the salient features of my inventionand I therefore intend the following claims to cover such modificationsas naturally fall within the lines of invention.

Having thus fully described my inven tion, what I claim and desire tosecure by Letters Patent is 1. Atell-tale switch consisting of ametaltube bent semi-circular, adapted to receive at each end and holdsecurelyglass tubes, one of these glass tubes provided with an adjustableelectrode, the other provided with means of connection to a vacuum pipe.

2. A tell-tale switch consisting of a metal tube bent semi-circularprovided with means for securing glass tubes, all mounted on. a

panel board; with mercury in the tube; one This specification signed andwitnessed V olfflthelse glass tubes provide]? with an eldjustthis 17 dayof Feb. A. D., 1914.

a e e ectrode the other tu e provide with connections td a vacuum, astandard battery JOHN HOWLAND' circuit connected to the electrode andthe In the presence 0fsemi-circular tube whereby a reduction in J. C;HOPWO0L,

vacuum closes the bell circuit. Jon DWYER. J r

